#include <stdio.h>
int main()
{ 
    int max4(int a,int b,int c,int d);
    int a,b,c,d, max;
    printf("Please enter 4 interger numbers:");
    scanf("%d %d %d %d",&a,&b,&c,&d);
    max=max4(a,b,c,d);
    printf("max=%d \n", max);
    return 0;
}
int max4(int a, int b, int c, int d)
{ 
    int max2(int a,int b);
    int m;
    m=max2(a,b);
    m=max2(m,c);
    m=max2(m,d);
    return(m);
}
int max2(int a,int b)
{ 
    if(a>=b)
        return a;
    else
        return b;
}